Studies of internal iron kinetics in experimental animals and in man continue. The in vivo loading and unloading of transferrin iron as well as the molecular aspects of iron absorption are being examined. Other studies relate to the effects of tissue iron deficiency on body function. Iron overload is being studied in the families of patients with idiopathic hemochromatosis and in the general population. The relationship between myelopoiesis and bone formation is beng studied in experimental animals and in thalassemia.